1. Field of the Invention
The present invention relates generally to conveyor belts. In particular, the present invention relates to multi-layered conveyor belts with reinforcing tier heavy-duty use.
2. Discussion of Background
In addition to simple wear, belts used to convey objects can be damaged in a number of ways. The objects they convey are a big factor in the type of damage. Broken glass and scrap metal, for example, can do a lot of damage to a conveyor belt very quickly. The following is a brief review of the sources of damage from objects generally.
In most industrial situations requiring the use of conveyor belts, the objects to be conveyed are dropped onto the conveyor belt from a stationary bin or hopper. Normally, such holding devices are a distance above the conveyor and consequently, when a load is delivered to the conveyor, it imparts impact stress upon the belt. Repeated load applications cause deformation and eventually stress failure. Thus, in order to have a long useful life, a belt must be able to withstand repeated stress applications.
Puncturing is another problem commonly encountered in the use of belts. When dropping sharp objects such as glass, stone, coal, or scrap metal onto the belt, the sharp edges penetrate the surface of the belt. Upon removal, such objects may make a hole or tear in the belt. Successive load applications containing sharp objects increase the number of punctures suffered by the belt and reduce its strength. Eventually, unless repairs are made, the belt will fail.
Another problem caused by the transportation of sharp objects is longitudinal splitting. Often it occurs that a sharp object penetrates the entire depth of the belt, that is, the object protrudes through to the bottom side of the belt. As the object is being conveyed, it may engage a structure or piece of equipment just above the conveyor (a "pinch" point). The object then is held stationary by the equipment as the belt continues to move. The object shears the belt longitudinally as long as it is held by the equipment. FIG. 4 illustrates this problem. As can be seen, sharp object 70 has penetrated prior art belt 80 and became lodged between belt 80 and structure 90. As belt 80 moves, it is longitudinally split by object 70.
There exists in the art many conveyor belts that have attempted to solve the above mentioned problems. It is known to provide a conveyor belt with reinforcing fabrics and rods. However, prior to the instant invention, there exists no conveyor belt which adequately solves the above mentioned problems, in the manner described in the specification, while maintaining flexibility, low weight and ease of manufacture.